Preparation of cyclomatic nickel nitrosyls



United States Patent 6 3,086,037 PREPARATION OF CYCLOMATIC NICKEL NiTROSYLS Thomas H. Coflield, Heidelberg, Germany, and Kryn G.

Ihrman, Farmington, Mich., assignors to Ethyl Corporation, New York, N.Y., a corporation of Virginia No Drawing. Filed Aug. 20, 1959, Ser. No. 834,930 3 Claims. (Cl. 260-439) This invention relates to a new and improved chemical process. More specifically, this invention relates to a novel process for forming cyclomatic nickel nitrosyl compounds which have great utility as antiknock additives in gasoline.

An object of this invention is to provide a new and useful process for forming organometallic coordination compounds. A further object of this invention is to provide a process for forming cyclomatic nickel nitrosyl compounds. Further objects will become apparent from a reading of the specification and claims which follow.

The above objects are accomplished by providing a novel process for the formation of cyclomatic nickel nitrosyl compounds. This process involves the reaction of a mixture comprising a tricyclomatic trinickel dicarbonyl compound and a cyclomatic nickel carbonyl dimer with nitric oxide. Although We are not bound by any theory as to the reaction mechanism, it is believed that our process can be represented by the following reactions:

As shown by the above, our process is represented as involving two reactions. The first involves reaction between one mole of a tricyclomatic trinickel dicarbonyl compound and three moles of nitric oxide to form three moles of a cyclomatic nickel nitrosyl compound and two moles of carbon monoxide. The second involves reaction between one mole of a cyclomatic nickel carbonyl dimer and two moles of nitric oxide to form two moles of a cyclomatic nickel nitrosyl compound and two moles of carbon monoxide.

The tricyclomatic trinickel dicarbonyl compound and cyclomatic nickel carbonyl dimer employed in our process may contain cyclomatic hydrocarbon groups containing from five to about 13 carbon atoms. In general, such cyclomatic hydrocarbon groups can be represented by the formula:

W RJQLRA where the R groups are selected from the group consisting of hydrogen and univalent hydrocarbon radicals. The cyclomatic groups are represented by Cy in the above equations. Typical of the cyclomatic groups which may be presented in the tricyclomatic trinickel dicarbonyl compound and the cyclomatic nickel carbonyl dimer are cyclopentadienyl, indenyl, methylcyclopentadienyl, pro pylcyclopentadienyl, diethylclopentadienyl, phenylcyclopentadienyl, tert-butyl cyclopentadienyl, p-ethylphenyl cyclopentadienyl, 4-tert-butyl indenyl and the like. These radicals are contained in the reactants tricyclopentadienyl trinickel dicarbonyl and cyclopentadienyl nickel carbonyl dimer, triindenyl trinickel dicarbonyl and indenyl nickel carbonyl dimer, tris(methylcyclopentadienyl) trinickel dicarbonyl and methylcyclopentadienyl nickel carbonyl dimer, tris (propylcyclopentadienyl) trinickel dicarbonyl and propylcyclopentadienyl nickel carbonyl dimer, tris(di- 5 ll RP 6 12 3,086,037 Patented Apr. 16, 1963 ice dienyl nickel carbonyl dimer, tris(tert-butyl cyclopenta-v dienyl) trinickel dicarbonyl and tert-butylcyclopentadienyl nickel carbonyl dimer, tris (p-ethylphenylcyclopentadienyl) trinickel dicarbonyl and p-ethylphenylcyclopentadienyl nickel carbonyl dimer, and the mixture of tris(4- tert-butylindenyl) trinickel dicarbonyl and 4- tertbutylindenyl nickel carbonyl dimer. The above reaction mixtures, when employed in our process, yield respectively cyclopentadienyl nickel nitrosyl, indenyl nickel nitrosyl, methylcyclopentadienyl nickel nitrosyl, propylcyclopentadienyl nickel nitrosyl, diethylcyclopentadienyl nickel nitrosyl, phenylcyclopentadienyl nickel nitrosyl, tert-butylcyclopentadienyl nickel nitrosyl, p-ethylphenylcycl-opentadienyl nickel nitrosyl and 4-tert-butylindenyl nickel nitrosyl.

When a particular mixture of a tricyclomatic trinickel dicarbonyl compound and a cyclomatic nickel carboynl dimer are employed as reactants in which the cyclomatic groups on the two compounds, are mixed, there is obtained a mixed cyclomatic nickel nitrosyl product. As an example of this, when a mixture of tricyclopent-adienyl trinickel dicarbonyl and methylcyclopentadienyl nickel carbonyl dimer are reacted with nitric oxide there is obtained a mixed product comprising cyclopentadienyl nickel nitrosyl and methylcyclopentadienyl nickel nitrosyl.

A preferred mixture for reaction with nitric oxide is that comprising tricyclopentadienyl trinickel dicarbonyl and cyclopentadienyl nickel carbonyl dimer. This reaction mixture is preferred since the cyclopentadienyl moiety present is the reactants is derived from cyclopentadiene, a readily available chemical of commerce. Further, the product, cyclopentadienyl nickel nitrosyl, formed when using this mixture as the reactant, is an extremely potent antiknock having great utility as a gasoline additive.

Our process may be readily carried out as essentially a liquid phase reaction. When so carried out, it is preferably conducted in an autoclave. The autoclave is equipped with inlet and outlet ports, pressure controls connected with side ports so that the pressure can be regulated in the autoclave, temperature controls and agitation means which disperse the reactants so that they intimately contact each other. The autoclave temperature in our process is maintained between about zero to about C. A preferred temperature range is from about 20 to about 40 C. since within this range the reaction goes readily with a minimum of said reactions. In gen eral, the pressure employed in the reaction vessel is not critical. Pressures ranging from one to about 50 atmospheres may be employed. Normally, however, the process is conducted at pressures ranging from about one to about five atmospheres.

A solvent is preferably used as a d-ispersent for the reactants in our process. The solvent is preferably free of air or oxygen, and one means by which this may be conveniently accomplished is by bubbling carbon monoxide through it or by heating it so as to expel any absorbed gases.

The nature of the solvent which may be used in our process is not critical. In general, any solvent can be utilized which does not react with the reactants employed in our process. Typical of applicable solvents are hydrocarbon and ether solvents. The hydrocarbon solvents may be aliphatic hydrocarbons such as n-hexane, n-octane, isooctane, n-heptane, various positional isomers of hexane, octane and heptane, or mixtures of the above. The solvent may also be a cycloaliphatic hydrocarbon such as cyclohexane or methylcyclohexane. Further applicable 3 solvents are cyclic olefins such as cyclohexene and methylcyclohexene. Straight and branched-chain olefins such as isoheptene, n-hexene, isooctene, isoheptene and the like are also applicable. Aromatic hydrocarbon solvents such as benzene, toluene, ethylbenzene and xylenes, ether mixed or pure, may also be used.

Typical of the ether solvents are the cyclic ethers such as tetrahydrofuran, 1,4-dioxane and 1,3-dioxane. Noncyclic monoethers such as diethylether, diisopropylether and diphenylether are good solvents for use in our process. Non-cyclic polyethers such as the dimethylether of ethyleneglycol, the diethylether of ethyleneglycol, the dibutylether of ethyleneglycol, the dimethylether of diethyleneglycol, the diethylether of diethyleneglycol and the dibutylether of diethyleneglycol are also excellent solvents for use in our process.

A preferred group of solvents for use in our process are the highly polar others such a tetrahydrofuran, ethyleneglycol dimethylether, ethyleneglycol diethylether, ethyleneglycol dibutylether, diethyleneglycol dimethylether, diethyleneglycol diethylether, diethyleneglycol dibutylether and the like.

Our solvents should preferably have a normal boiling point which varies by at least 25 C. from the normal boiling point of the product. A variation of at least 25 C. between the normal boiling points of the product and solvent aids greatly in separation of the product from the solvent by means of distillation.

The ratio of tricyclomatic trinickel dicarbonyl compound to cyclomatic nickel carbonyl dimer in the reaction mixture is not critical. Any ratio of the two components works satisfactorily in our process since either component will react readily with nitric oxide to form a cyclomatic nickel nitrosyl compound. Ordinarly, excess nitric oxide is employed in our process. This excess is preferably on the order of 50 to 100 percent. There are generally employed from about .30 to about .42 parts of nitric oxide for each part of mixed reactant. This quantity of nitric oxide is such that it insures about a 50 percent excess when the mixed nickel reactant is almost entirely tricyclomatic trinickel dicarbonyl compound or when it is almost entirely cyclomatic nickel carbonyl dimer. Greater or lesser quantities of nitric oxide can be used in our process. The use, however, of 'at least about 50 percent excess of nitric oxide helps to insure that most of the nickel reactants are consumed in the reaction. This is desirable since they are more expensive than the nitric oxide.

In conducting our process, air is preferably excluded from the reaction mixture. Otherwise, some deterioration is likely to occur. Air is readily excluded by using in the system a blanketing gas of nitric oxide. Since carbon monoxide is a product of the reaction, the blanketing gas will also contain some carbon monoxide. The out gases containing nitric oxide and carbon monixide may be recycled to the autoclave.

The reaction mixture is preferably agitated so as to insure homogeneity of the reaction mass. In the autoclave, there are generally present both gases and liquids, and agitation insures that these phases are well dispersed. Without agitation, the gaseous reactants may tend to collect in the upper portion of the autoclave, while the liquid reactants settle to the bottom of the autoclave. When this occurs, the reaction rate is diminished. Agitation is, therefore, desirable in insuring a constant reaction rate.

Tricyclomatic trinickel dicarbonyl compounds and cyclomatic nickel carbonyl dimer compounds are reported in the literature and may be made by the reaction of nickel tetracarbonyl with a dicyclomatic nickel compound. Further, it is reported in the literature that cyclomatic nickel carbonyl dimer compounds may be converted to tricyclomatic trinickel dicarbonyl compounds by prolonged heating at elevated temperatures.

To further illustrate the process of our invention, there Example I A mixture of cyclopentadienyl nickel carbonyl dimer and cyclopentadienyl nickel carbonyl trimer was made as follows: A stirred solution comprising 9.5 parts of dicyclopentadienyl nickel, 13.1 parts of nickel tetracarbonyl and 88.8 parts of tetrahydrofuran was slowly heated to reflux under a nitrogen atmosphere. Exit gases were passed through a Dry Ice trap to remove unreacted nickel tetracarbonyl. The mixture darkened after 45 minutes and turned a deep-purple after minutes. The heating was continued for a total of 21 hours. At this time, unreacted nickel tetracarbonyl was deliberately swept into the Dry-Ice trap by passing a slow stream of nitrogen through the hot solution for five minutes. The system was cooled to room temperature, and nitric oxide was passed through the mixture of the two carbonyl compounds for six hours. Lastly, nitrogen was again bubbled through the mixture and through the Dry-Ice trap to insure complete removal of nickel tetracarbonyl from the system. The mixture is filtered, and the filtrate is fractionally distilled. The cut boiling at 6264 C. at 30 mm. gave 10.53 parts of cyclopentadienyl nickel nitrosyl.

Example H Thirty-two and five tenth partsof tricyclopentadienyl trinickel dicarbonyl, 10 parts of cyclopentadienyl nickel carbonyl dimer, 18 parts of nitric oxide and 1000 parts of diethyleneglycol dibutylether are charged to an evacuated autoclave equipped with inlet and discharge ports, temperature control means, pressure control means and an agitator. The autoclave is maintained at a temperature of 30 C. and a pressure of one atmosphere. The reaction mixture is agitated for two hours whereupon the autoclave is discharged. The reaction mixture is distilled to give a good yield of cyclopentadienyl nickel nitrosyl in the distillate. The residual solvent is filtered and recycled to the autoclave.

Example III Forty and five tenth parts of tricyclopentadienyl trinickel dicarbonyl, two parts of cyclopentadienyl nickel carbonyl dimer, 13.5 parts of nitric oxide and 1600 parts of benzene are charged to an evacuated reaction vessel equipped as in Example II. The reaction mixture is agitated for four hours at a temperature of 40 C. and a pressure of one atmosphere. The autoclave is then cooled and discharged, and the reaction mixture is filtered. The filtrate is distilled to give a good yield of crude cyclopentadienyl nickel nitrosyl in the residue. The benzene filtrate is recycled to the reaction vessel. The residues are further distilled to give essentially pure cyclopentadienyl nickel nitrosyl.

Example IV One part of tricyclopentadienyl trinickel dicarbonyl, 42 parts of cyclopentadienyl nickel carbonyl dimer, 20 parts of nitric oxide and 1200 parts of ethyleneglycol dimethylether are charged to an evacuated autoclave equipped as in the previous examples. The reaction mixture is agitated for one hour at a pressure of five atmospheres and a temperature of 20 C. The autoclave is then discharged, and the contents are filtered. The filtrate is distilled to give a good yield of crude cyclopentadienyl nickel nitrosyl in the residue. The ethyleneglycol dirnethylether filtrate is recycled to the reaction Vessel. The crude cyclopentadienyl nickel nitrosyl is further purified by flash distillation to give a good yield of essentially pure cyclopentadienyl nickel nitrosyl.

Example V Seven parts of tris(methylcyclopentadienyl) trinickel dicarbonyl, 40 parts of methylcyclopentadienyl nickel carbonyl dimer, 13.5 parts of nitric oxide and 600 parts of tetrahydrofuran are charged to an evacuated autoclave. The mixture is agitated for three hours at a temperature of 30 C. and a pressure of two atmospheres. The auto- Example VI Thirty-seven and five tenth parts of tr-is( indenyl) trinickel dicarbonyl, 20 parts of indenyl nickel carbonyl dimer, 30 parts of nitric oxide and 2500 parts of n-octane are charged to a reaction vessel equipped as in the preceding examples. The reaction mixture is agitated at a temperature of 50 C. and a pressure of atmospheres for six hours. The autoclave is then cooled and discharged. The reaction product is purified by distillation to give a good yield of crude indenyl nickel nitrosyl in the residue. The filtrate comprising the n-octane solvent is recycled to the autoclave.

As shown by the preceding examples, our process goes readily when using a wide range of process conditions and a wide variety of nickel-containing reactants. For example, when a mixture of tris(phenylcyclopentadienyl) trinickel dicarbonyl and phenylcyclopentadienyl nickel carbonyl dimer is utilized as a reactant in the above process, the product, phenylcyclopentadienyl nickel nitrosyl, is obtained. Likewise, when a mixture of tris(di-tertbutylcyclopentadienyl) trinickel dicarbonyl and di-tertbutylcyclopentadienyl nickel carbonyl dimer, tris(n-hexylcyclopentadienyl) trinickel dicarbonyl and n-hexylcyclopentadienyl nickel carbonyl dimer or tris(tetramethylcyclopentadienyl) trinickel dicarbonyl and tetramethylcyclopentadienyl nickel carbonyl dimer are utilized as reactants in the above process, the compounds di-tert-butylcyclopentadienyl nickel nitrosyl, n-hexylcyclopentadienyl nickel nitrosyl and tetramethylcyclopentadienyl nickel nitrosyl are obtained in good yield. 7

Our process may also be carried out essentially as a gas phase reaction. In this embodiment of our process, a gaseous mixture of a tricyclomatic trinickel dicarbonyl compound and a cyclomatic nickel carbonyl dimer compound are fed, along with nitric oxide, through a heated tube reactor. The reactor is packed with suitable particulate material to insure intimate mixing of the components. The cyclomatic nickel nitrosyl product may be separated from the out gases by conventional means such as passing the gases through a cooling system and condensing out the product with unreacted tricyclomatic trinickel dicarbonyl and cyclomatic nickel carbonyl dimer. The product is separated from the nickel reactants by conventional means such as extraction or distillation. The sep arated tricyclomatic trinickel dicarbonyl compound and cyclomatic nickel carbonyl dimer are recycled to the reactor. The out gases from the condenser may also be recycled to the reactor.

The cyclomatic nickel nitrosyl compounds produced by our process are excellent antiknocks. They have been tested by the Research Method to determine their antiknock effect in a hydrocarbon fuel. The Research Method of determining octane number of the fuel is generally accepted as a test method which gives a good indication of fuel behavior in full-scale automotive engines under normal driving conditions. It is the method most used 5 by commercial installations in determining the value of a gasoline additive.

The Research Method is conducted in a single cylinder engine especially designed for this purpose and referred to as the CFR engine. This engine has a variable compression ratio and during the test the temperature of the water jacket is maintained at 212 F., and the inlet air temperature is controlled at F. The engine is operated at aspeed of 600 rpm. with a spark advance of 13 before top dead center. This test method is more fully described in Test Procedure D908-55 contained in the 1956 edition of ASTM Manual of Engine Test Methods for Rating Fuels.

The fuel employed in these tests was a mixture representative of commercial gasolines in present production. It consisted of 20 volume percent diisobutylene, 20 volume percent toluene, 20 volume percent isooctane and 40 volume percent n-heptane. This fuel, when rated without an antiknock additive, had a research octane number of 91.3. When the fuel contained one gram of nickel per gallon in the form of a typical compound produced by our process, cyclopentadienyl nickel nitrosyl, it had a research octane number of 93.8. Two grams of nickel per gallon as cyclopentadienyl nickel nitrosyl raised the octane number of the base fuel to 95.0. i

In addition, cyclopentadienyl nickel nitrosyl was tested as a supplemental antiknock. In this test, one gram of nickel per gallon as cyclopentadienyl nickel nitrosyl was added to a base fuel which contained three milliliters of tetraethyllead per gallon. The presence of the nickel additive resulted in an increase of 3.4 octane numbers over that obtainable with the tetraethyllead alone. This increase represents an outstanding improvement in antiknock effectiveness.

Although the process of our invention has been illustrated only with respect to the production of cyclomatic nickel nitrosyl compounds, it works equally as well in producing similar compounds of platinum and palladium.

Having fully described our novel and inventive process by the foregoing examples and discussion, we desire that our invention be limited only within the scope of the appended claims.

We claim:

1. Process for formation of a cyclomatic nickel nitrosyl compound in which the cyclomatic group is a hydrocarbon radical containing from 5 to about 13 carbon atoms and is selected from the class consisting of the cyclopentadienyl radical, the indenyl radical, and substituted cyclopentadienyl and indenyl radicals, wherein the hydrocarbon substituents are selected from the class consisting of alkyl, phenyl, and alkylphenyl radicals; said process comprising reacting a mixture of the tricyclomatic nickel dicarbonyl compound and the cyclomatic nickel carbonyl dimer compound both containing the corresponding cyclomatic radical, with nitric oxide.

2. The process of claim 1 wherein the reaction is carried out in essentially the liquid phase.

3. The process of claim 1 wherein the mixture of tri-, cyclomatic trinickel dicarbonyl compound and cyclomatic nickel dimer compound comprises tricyclopentadienyl trinickel dicarbonyl and cyclopentadienyl nickel carbonyl dimer, and the product formed is cyclopentadienyl nickel nitrosyl.

References Cited in the file of this patent 

1. PROCESS FOR FORMATION OF A CYCLOMATIC NICKEL NITROSYL COMPOUND IN WHICH THE CYCLOMATIC GROUP IS A HYDROCARBON RADICAL CONTAINING FROM 5 TO ABOUT 13 CARBON ATOMS AND IS SELECTED FROM THE CLASS CONSISTING OF THE CYCLOPENTADIENYL RADICAL, THE INDENYL RADICAL, AND SUBSTITUTED CYCLOPENTADIENYL AND INDENYL RADICALS, WHEREIN THE HYDROCARBON SUBSTITUENTS ARE SELECTED FROM THE CLASS CONSISTING OF ALKYL, PHENYL, AND ALKYPHENYL RADICALS, AND PROCESS COMPRISING REACTING A MIXTURE OF THE TRICYCLOMATIC NICKEL DICARBONYL COMPOUND AND THE CYCLOMATIC NICKEL CARBONYL DIMER COMPOUND BOTH CONTAINING THE CORRESPONDING CYCLOMATIC RADICAL, WITH NITRIC OXIDE. 